The present invention relates to a seat for a motor vehicle, particularly for a passenger car, having a base element which can be fastened in the motor vehicle, a seat element which is disposed on the base element, and a backrest element which is disposed on the seat element. The seat is adjustable between a locked position, in which the seat element and the backrest element can be used for normal sitting, and an unlocked position. In the unlocked position, at least one of the seat element and the backrest element is adjusted in the vehicle to the front with respect to the driving direction sufficiently far that a space arranged behind the seat with respect to the driving direction is accessible for loading, unloading, entry and exit. The seat element is swivellably disposed on the base element for adjusting the seat between the locked position and the unlocked position. Damper devices counteract, in a damping manner, a restoring movement of the seat from its unlocked position into its locked position.
A front passenger seat of this type for a bus is known from German Patent Document DE 38 01 294 A1. This known seat comprises forward frame legs which are fixed to the vehicle body and on which a seat element is swivellably disposed. In addition, a backrest element is swivellably disposed on the seat element. In order to be able to open up the entrance area of the bus for entry and exit, the seat can be adjusted between a locked position, in which the seat element and the backrest element can be used for normal sitting, and an unlocked position, in which the seat element and the backrest element are adjusted forward in the vehicle with respect to the driving direction. Damper devices in the form of gas pressure springs are provided between the forward frame legs and the seat element in order to facilitate forward displacement of the seat. During return displacement of the seat from its unlocked position into its locked position, these damper devices counteract the restoring movement of the seat in a correspondingly damping manner.
In this known seat, the backrest as well as the seat element must be displaced and secured in a corresponding position. Consequently, a complex and high-expenditure locking mechanism is required for the backrest and the seat element. Such a complex locking mechanism requires relatively high operating and control expenditures, for example, to determine whether the seat is properly locked in the in-use position.
A rear seat for a motor vehicle which can be moved from an in-use position into a not-in-use position is known from German Patent Document DE 41 36 363 A1. For this purpose, the seat element is swivelled about a swivelling axis, which is arranged on an end situated away from the backrest, before the backrest can be brought about a swivelling axis provided in its lower area into a horizontal position. The seat element and the backrest are connected with one another by way of gas pressure springs which, in a damping manner, counteract movements of the seat from the in-use position into the not-in-use position and vice versa.
Finally, each of the seats known from German Patent Document DE 39 34 171 C2 as well as from German Patent Document DE 38 13 594 A1 has a seat element and a backrest element disposed thereon. Normally, such a seat is also equipped with a base element which can be fastened in the motor vehicle and on which the seat element is disposed. The known seats can be adjusted between a locked position and an unlocked position. In the locked position, the seat element and the backrest element can be used for normal vehicle occupant sitting. In the unlocked position, the backrest element is adjusted in the vehicle with respect to the driving direction toward the front so that a space arranged behind the seat with respect to the driving direction, such as the rear space, is accessible for loading or unloading and entry and exit of rear occupants. In order to be able to adjust the seat between its locked position and its unlocked position, the backrest element is in this case swivellably disposed on the seat element.
In the last mentioned seats, spring devices in the form of elastic components are arranged between the backrest element and the seat element. A flexible buffer or a compression-elastic elastomer part constructed as a rubber part or a soft-plastic part, in particular, may be used. These spring devices have the purpose of bracing, in the locked position of the seat, the backrest element with respect to the seat element such that relative movements between these elements and thus noise development are prevented.
It is an object of the present invention to reduce the operating expenditures when displacing the seat back into its locked position while a comfortably damped restoration of the seat into position is maintained.
According to the invention, this object is achieved by a seat in which the damper devices are dimensioned such that, during a restoring movement, the seat, because of its weight, is automatically adjusted into its locked position. The restoring movement of the seat is damped during an end phase until the locked position is reached. Advantageous embodiments with expedient further developments of the invention are reflected in the claims.
In order to increase comfort of the seat according to the invention, the restoring movement of the seat is damped during an end phase until the locked position is reached. As a result of this measure, the kinetic energy of the seat during the restoring adjustment is converted into frictional or thermal energy. The damping effect, that is, the damper forces counteracting the restoring movement, depend on the speed of the restoring movement so that higher restoring speeds cause correspondingly higher damper forces. The corresponding seat components, such as a locking mechanism, are therefore protected. As a result, the operational safety of the vehicle can also be improved. As the end phase of the restoring movement, that is, the part of the restoring path damped by the damper devices becomes longer, the kinematic energy of the seat becomes lower and slamming of the seat into its locked position can be better prevented by damper devices.
Furthermore, in a seat according to the invention, the damper devices are dimensioned such that, during the restoring movement, because of its weight, the seat is automatically adjusted into its locked position. The operating expenditures of the seat are therefore reduced because the need for the vehicle occupant to check as to whether the seat has reached its locked in-use position is eliminated. This is particularly significant if the seat has an automatically operating locking device which secures the seat as soon as it has reached its locked position.
In one preferred embodiment, the damper devices can be constructed as piston-cylinder units which may be constructed as gas pressure springs or as oil pressure dampers. Such damper devices, which are known per se, permit, the damped end phase of the restoring movement to be constructed so as to be particularly large. Furthermore, such damper devices are relatively reasonably priced, have been successful in practice, and can be designed in a relatively simple manner for the forces to be controlled at the seat.
In a further development of the seat according to the invention, locking devices may be provided which automatically lock the seat when its locked position is reached. These locking devices may then have a swivel bow which can be swivellably adjusted about a swivel shaft between a holding position, in which it reaches, by way of a bow part, over a projection which is necessarily also adjusted by the adjusting movement of the seat between its locked position and its unlocked position, and a release position, in which it releases the projection. The damper devices, which in this case are constructed as piston cylinder units for damping the restoring movement, can then extend through between the bow part of the bow situated in its release position and the swivel shaft and can be supported on the projection. As a result, a compact construction, which permits favorable lever ratios for the introduction of force of the dampers, is obtained.
Additional important characteristics and advantages of a seat according to the invention are reflected in the claims, the drawings, and the description of the figures shown in the drawings.
It is to be understood that the characteristics mentioned above and the characteristics yet to be explained can be used not only in the particularly described combination but also in other combinations or alone, without departing from the scope of the present invention.